Elk are big animals, and they're extremely tough. While shot placement is key, you also need plenty of gun for a clean kill. Here's a look at the various calibers.
.270 In the eyes of most, the .270 Win. represents the lower end of decent elk cartridges. The 150-grain bullet has a sectional density of .279, and muzzle velocities of factory ammo in this weight run about 2,900 fps. At 200 yards, you're looking at 2,000 ft.-lbs. of energy--sufficient but not awe-inspiring. The .270 WSM whips up 300 fps more speed, with 200-yard energies starting at 2,130 ft.-lbs. The only other member of the class, the .270 Wby. Mag., is more powerful yet (3,245 fps muzzle velocity, 2,655 ft.-lbs. energy at 200 yards).
7mm The 7mm Rem. Mag. offers a great selection of factory ammo options--bullets of 160 grains (sectional density .283) and 175 grains (.310 SD). The 160s start out at just under 3,000 fps and produce more than 2,100 ft.-lbs. of energy at 200 yards. The 175s are about 100 fps slower at the muzzle but generate more than 2,300 ft.-lbs. at 200 yards.
The newcomer 7mm WSM is no slouch. It launches a 160-grain bullet at about the same speed as the Remington long-action round but isn't available in heavier bullet weights.
The biggest and fastest of the bunch--magnums like the STW, Ultra Mag, Weatherby and Lazzeroni--are more limited in selection but provide more power for those who want it.
Good news for .280 Rem. fans: Federal has a new 160-grain AccuBond load--2,800 fps at the muzzle and 2,155 ft.-lbs. at 200 yards--that would make a good choice.
.30 America's favorite caliber offers the widest selection for elk hunters. At the low end, there's the 165-grain .308 Win. punching out its .226 SD bullet in the neighborhood of 2,700 to 2,800 fps for 200-yard energies right around the 2,000 ft.-lbs. mark.
The venerable .30-06 is a great pick with 180-grain bullets (.271 SD). Leaving the muzzle at 2,700 fps, you'll get more than 2,200 ft.-lbs. of energy at 200 yards, and you can improve on that considerably by looking at Hornady's Light Magnum or Federal's High Energy loads.
Stepping up to magnum performance levels, you've got three short mags (.300 WSM, .300 SAUM, .308 Patriot) and six long mags (.300 Win. Mag., .300 Ultra Mag, .300 Wby. Mag., .300 Dakota, .308 Warbird, .300 H&H Mag.)
Elk hunters opting for most any of the latter can move up to 200-grain bullets (.301 SD), although with today's bullets the 200-grainer seems to be falling by the wayside. In fact, the Big Kahuna of the major-factory bunch, Remington's Ultra Mag, isn't even available in a 200, although when it's pushing a 180-grain Core Lokt Ultra out the muzzle at 3,250 fps and churning up more than 3,000 ft.-lbs. of energy at 200 yards, who cares?
.325 and Up Until recently there was only one cartridge to bridge the gap between .30 and .338, and that was the excellent 8mm Rem. Mag.--excellent but not popular. Now we have the .325 WSM, available in 180- and 200-grain (.274 SD) weights. The .325's 200-grainer leaves the muzzle at 2,950 fps and hits a 200-yard target with nearly 3,000 ft.-lbs. of energy.
The .338 Win. Mag. has long been the standard for those who like big elk guns. It can push a 225-grain bullet (.281 SD) at 2,800 fps for more than 3,000 ft.-lbs. of energy at 200, and if that's not enough stuff, check out the .338 Ultra Mag with a 250-grain bullet (.313 SD): 2,806 fps at the muzzle, 3,300 ft.-lbs. energy at 200.
Those who love the timber may look to the big .45 calibers such as the .450 Marlin or a hot .45-70 in a strong, modern gun--or, of course, the venerable .35 Whelen. We'll leave those discussions for another time.